template<typename E> class Queue{
	private:
	void operator=(const Queue&){}
	Queue(const Queue&){}
	
	public:
	Queue(){}
	virtual ~Queue(){}
	
	virtual void clear()=0;
	
	virtual void enqueue(const E&)=0;
	
	virtual E dequeue()=0;
	
	virtual const E& frontValue() const=0;
	
	virtual int length() const=0;
}